1. Field of the Invention
The present invention relates to a validation apparatus for validating flat paper objects, and particularly to a bill validation apparatus, such as ATM (Automated Teller Machines) or CD (Cash Dispensers), for validating outer dimensions, watermark patterns, print patterns or the like elements on such objects.
2. Prior Art
Vending machines or money changing machines, such as ATM or CD, for delivering articles or coins have a bill validating apparatus for validating inserted bills built-in.
As shown in FIG. 13(a), a bank bill 1 is transferred by a conveying means 2 such as a belt or the like. When the bill 1 reaches at a predetermined position, data on print patterns of the bill 1 are detected by a reflected light sensor 3 provided over the conveying means 2 as the bill is transferred. The detected data are compared with print pattern data of the corresponding true bills stored in a memory.
The sensor 3 comprises a light emitter 4 and a light detector 5. The light emitter 4 uses an LED or the like means as light source for generating a beam of visible light, and the light beam generated by the emitter 4 is irradiated and reflected on the surface of the bill 1.
Since the amount of reflected light changes in response to shades of colors of the print pattern, the light detector 5 detects the reflected light, and the pattern of the bill 1 is obtained by converting the amount of reflected light into an electric signal.
However, it is difficult to detect and reject forged bills that are produced by color copying machines by the conventional bill validating apparatus described above.
To solve that problem, it has been common to use a bill validating apparatus for detecting watermarks together with the print patterns of the bank bill 1 as shown in FIG. 13(b). The validating apparatus is provided with a transmitted light sensor 8, in place of the sensor 3, including a light detector 6 disposed above the conveying path of the bill 1 and a light emitter 7 located below the path so as to obtain print pattern data and watermark pattern data of the bill 1. The detected data are compared with the print pattern data and watermark pattern data of the true bill stored in a memory.
However, by the conventional bill validating apparatus, it is also difficult to detect and reject forged bills that are produced by color copying machines using transmitted light because the forged bills include watermark patterns therein. For carrying out more accurate validation, it is necessary to use an identification method for detecting magnetism included in ink of the bills and comparing it with magnetism patterns of true ones stored in a memory in combination with the above validation method using reflected or transmitted light.
Thus, a combination validation method requires various and a great amount of data on the true bank bills for comparison to the detected data. In addition, it is equally possible whether each bank bills is transferred to the sensor forward or backward with its right or reverse side, the bill validating apparatus must require data for such four kinds of insertion conditions.
Therefore, a so-called Multi-Currency Bill Validator that is capable of validating bank bills of a plurality of countries by one machine further requires a great amount of data in proportion to the number of bank bills to be processed therein. Accordingly, both a high-speed CPU and large capacity memories must be required to avoid lowering the operation speed to be caused by the above restrictions. Thus, the manufacturing cost has been inevitably high.
In addition, even in the case of bill validators provided with both large capacity memories and a high-speed CPU, there still remain problems of rejecting true bank bills due to noises derived from their folds or stains, and there also remain problem of mistaking forged bank bills for true ones because the magnetic characteristics of copying ink (toner) used in some color copying machines are similar to those of true bank bills.